wd45 no spark

Mike in Ohio · Jun 15, 2015

It was missing badly so I got new plugs, points, condenser, cap and rotor. Now it has no spark, I got a new coil, still no spark. I have 12 volts going into the coil, all gaps set right. I am at a loss.

It was converted to 12 volts before I got it, but has been running fine for the 6 or 7 years I have had it. I am wondering if I got a bad coil, Napa didn't have a second one to exchange, but are ordering one.

What else could it be??

Thanks for the help.

JMS/.MN · Jun 15, 2015

Did you install points and condenser properly? ie, not shorted out...

Mike in Ohio · Jun 15, 2015

I think so, what would cause them to short out. Both are hooked to the lug that goes through the side of the distributor and screwed down to their respective screw holes.

old · Jun 15, 2015

Very easy to install points etc and short hing out. All it takes it having a hook up not right and a 1/32 inch is enough to short things out. Throwing part at it does not help a bit you need to trouble shoot then parts not parts then trouble shoot

John T · Jun 16, 2015

12 volts going INTO the coil when Ignition is ON is correct for a 12 volt tractor and 12 volt coil...

HOWEVER its what's coming OUT of the coil to distributor that also matters.

Place a test lamp on the coils output to distributor terminal, turn her on, and as the engine cranks over slowly it should flash ON (points open) and OFF (points closed). If it never comes ON the points may not be opening (are they gapped correct) or the condenser is bad/shorted, or theres a short from coil to distributor such as where the wire passes thru the distributors side or the points or points wiring is shorted. If it never goes OFF, points aren't closing fully (check that and their gap) or are bad or the wires open from coil or inside distributor to points.

If you take the time to work through my Ignition Troubleshooting Procedure linked below, it can help find the cause of no spark. No sense in re inventing the wheel each time this is asked LOOK AT MY FULL TEST PROCEDURE

I suspect a problem with points or points gap or theres a constant short or your wiring.

http://www.ytmag.com/cgi-bin/viewit.cgi?bd=farmall&th=5745

John T
John Ts Ignition Troubleshooting

Mike in Ohio · Jun 16, 2015

Thanks a lot for your reply.

One quick question, in your troubleshooting link, is the "high side" of the coil the positive side?

When it was converted from 6 to 12 volt, I don't think they did everything right, the coil was wired ignition switch to the negative side of the coil, and positive side to the distributor, but it ran that way for the 6 or 7 years we have had it.

Will take your troubleshooting plan to the shop this weekend and get things figured out. Thanks again.

RalphWD45 · Jun 17, 2015

Mike! I don't mean to gang up on you, but JMS, and old, both have a point! It was running , before you changed the points, and condenser, and now has no spark. It is common to ground out the points, due to the condenser wire, and the point spring, fastening to the hot screw coming into the side of the distributer. That is hard to see, and is the most common place for it to be grounded to the dist. Check this connection first, and don't try to overthink the problem, and start blaming the coil, ect.

John T · Jun 17, 2015

High side is INPUT from Ignition Switch,,,,,,,,Low side is OUTPUT to distributor.

Correct coil wiring for POS ground is: - becomes High INPUT from Ign switch, + is Low OUTPUT to distributor

Correct soil wiring for NEG ground is: + becomes High INPUT from Ign switch, - is Low OUTPUT to distributor.

It can still fire with coil reversed but its less efficient. Best if coil polarity matches battery.

John T

wd45 no spark

Mike in Ohio

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JMS/.MN

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Mike in Ohio

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old

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Mike in Ohio

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John T

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